JP5346155B2 - Styrene copolymer stretch molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stretched molding of a styrenic copolymer excellent in heat resistance, toughness, and transparency. <P>SOLUTION: The stretched molding of a styrenic copolymer is prepared by stretching a styrenic copolymer which is constituted of 5-99 mol% styrene derivative unit and 95-1 mol% olefin unit, has a syndiotactic structure having a stereoregularity [rrrr] of a repeating unit chain constituted of the styrene derivative of not less than 80% and a molecular weight distribution of not more than 1.3. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a styrene copolymer stretch-molded article, and more specifically, a styrene copolymer having excellent mechanical strength, heat resistance, and transparency using a styrene copolymer having a high syndiotactic structure. The present invention relates to a combined stretch molded product.

Polystyrene resins are generally brittle and have a significant problem of poor impact resistance, and syndiotactic polystyrene having excellent heat resistance has the same problem. Therefore, for the purpose of improving such problems, a copolymer of a styrene monomer and an olefin such as ethylene has been proposed. (For example, refer to Patent Document 1). In addition, a molded product of a styrene polymer having a highly syndiotactic structure has been proposed (for example, see Patent Document 2).
When a styrenic polymer having a high degree of syndiotactic structure is stretched, a stretch-molded product with improved mechanical strength, particularly elastic modulus, can be obtained. Depending on the application, stretch-molding with even better transparency and toughness can be obtained. Goods (films, sheets, etc.) are desired.
Moreover, although a syndiotactic polystyrene stretched film is excellent in mechanical strength, there exists a problem that toughness is inferior. In order to improve this problem, toughness is improved by using a styrene copolymer obtained by copolymerizing a styrene derivative and another compound. However, a stretched film made of a styrenic copolymer having further excellent toughness is desired.

International Publication No. 2006/004068 Pamphlet JP-A-63-77905

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a styrene copolymer stretch-molded article excellent in heat resistance, toughness, and transparency.

As a result of intensive research, the present inventors have found that a styrene copolymer having a high degree of syndiotactic structure and a molecular weight distribution within a specific range, comprising a styrene derivative unit and an olefin unit having a specific copolymerization ratio. It has been found that the above object can be achieved by using a polymer. The present invention has been completed based on such findings.
That is, the present invention provides the following styrene copolymer stretch-formed product.
1. It has a syndiotactic structure consisting of 5 to 99 mol% of styrene derivative units and 95 to 1 mol% of olefin units, and the stereoregularity [rrrr] of the repeating unit chain composed of styrene derivatives is 80% or more. A styrene copolymer stretch molded article obtained by stretching a styrene copolymer having a molecular weight distribution of 1.3 or less.

  According to the present invention, it is possible to obtain a styrene copolymer stretch-molded product having excellent heat resistance, toughness, and transparency.

The styrene copolymer used in the present invention comprises 5-99 mol% of styrene derivative units and 95-1 mol% of olefin units. As the styrene derivative forming the styrene derivative unit, styrene, alkyl styrene, halogenated styrene, alkoxy styrene, vinyl benzoate and the like are used.
Examples of the alkyl styrene include p-methyl styrene, p-ethyl styrene, p-propyl styrene, p-isopropyl styrene, p-butyl styrene, pt-butyl styrene, o-methyl styrene, o-ethyl styrene, o-propyl. Examples include styrene, o-isopropyl styrene, m-methyl styrene, m-ethyl styrene, m-isopropyl styrene, m-butyl styrene, 2,4-dimethyl styrene, 2,5-dimethyl styrene, and 3,5-dimethyl styrene. It is done. Examples of the halogenated styrene include p-chlorostyrene, m-chlorostyrene, o-chlorostyrene, p-bromostyrene, m-bromostyrene, o-bromostyrene, p-fluorostyrene, m-fluorostyrene, and o-fluoro. Examples thereof include styrene and o-methyl-p-fluorostyrene. Examples of alkoxystyrene include p-methoxystyrene, o-methoxystyrene and m-methoxystyrene. Examples of the vinyl benzoate include methyl p-vinyl benzoate, methyl m-vinyl benzoate and methyl o-vinyl benzoate.

Examples of the olefin forming the olefin unit constituting the styrene copolymer include ethylene, propylene, 1-butene, 3-methyl-1-butene, 4-phenyl-1-butene, 1-pentene and 3-methyl- 1-pentene, 4-methyl-1-pentene, 3,3-dimethyl-1-pentene, 3,4-dimethyl-1-pentene, 4,4-dimethyl-1-pentene, 1-hexene, 4-methyl- Examples include 1-hexene, 5-methyl-1-hexene, 6-phenyl-1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene and 1-icocene. It is done. In the present invention, those having 2 to 10 carbon atoms are preferred, and ethylene is particularly preferred.
The styrene copolymer is composed of 5 to 99 mol% of a styrene derivative unit and 95 to 1 mol% of an olefin unit, and the content ratio of the olefin unit is preferably 90 to 10 mol%, more preferably. 80 to 20 mol%. When the content ratio of the olefin unit is 1 mol% or more, the toughness in the styrenic copolymer is sufficient, so that the elongation in the case of a stretch-molded product (film, sheet, etc.) is sufficient. In addition, when the content ratio of the olefin unit is 95 mol% or less, a decrease in the melting point of the styrene copolymer is suppressed, and the heat resistance in the case of a stretch-molded product (film, sheet, etc.) is sufficient. Become.

The styrene copolymer used in the present invention requires that the stereoregularity [rrrr] of the repeating unit chain composed of the styrene derivative is 80 mol% or more, preferably 90 mol% or more, more preferably It is 95 mol% or more. When this stereoregularity [rrrr] is 80 mol% or more, the physical properties as syndiotactic polystyrene are expressed in the styrene copolymer. This stereoregularity [rrrr] can be calculated from data obtained by measuring NMR (particularly ¹³ C-NMR) of the styrene copolymer.

Further, the styrene copolymer used in the present invention has a molecular weight distribution of 1.3 or less. When the molecular weight distribution is 1.3 or less, uniformity in the stretch-formed product is maintained. The molecular weight of the styrene copolymer used in the present invention is not particularly limited, but is preferably in the range of 10,000 to 1,000,000 in terms of weight average molecular weight from the viewpoint of impact resistance.
The molecular weight distribution is measured by a gel permeation chromatography (GPC) method (measured at 145 ° C. using polystyrene as a standard substance and 1,2-dichlorobenzene as an eluent) / weight average molecular weight (Mw) / It means a number average molecular weight (Mn) ratio, and can be measured using, for example, a GPC measuring apparatus (TOSOH HLC 8121 GPC / HT).

The styrene copolymer used in the present invention can be produced by polymerizing the olefin and the styrene derivative using, for example, a catalyst composition described in International Publication No. 2006/004068. The catalyst composition is
1) a central metal M which is a Group 3 metal atom or a lanthanoid metal atom, a ligand Cgo containing a substituted or unsubstituted cyclopentadienyl derivative bonded to the central metal, monoanionic ligands Q1 and Q2, And a metallocene complex represented by the general formula (I) containing 2 neutral Lewis bases L, and 2) a polymerization catalyst composition comprising an ionic compound composed of a non-coordinating anion and a cation.

  In the general formula (1), M is a central metal in the metallocene complex. The central metal M is a Group 3 metal or a lanthanoid metal, and is not particularly limited. Since the metallocene complex used in the present invention can be used as one component of the polymerization catalyst composition, the central metal M is appropriately selected depending on the type of monomer to be polymerized. Examples of the central metal M include scandium Sc, gadolinium Gd, yttrium Y, holmium Ho, lutetium Lu, erbium Er, dysprosium Dy, terbium Tb, and thulium Tm. Sc, Gd, Y and Lu are preferred, and Sc is particularly preferred.

In the general formula (1), Cp ^* is a ligand containing a cyclopentadienyl derivative and is π-bonded to the central metal M. The ligand is preferably a non-bridged ligand. Here, the non-bridged ligand means a ligand having a coordination atom or a coordination group other than the cyclopentadienyl derivative, wherein the cyclopentadienyl derivative is π-bonded to the central metal.
Examples of the cyclopentadienyl derivative contained in Cp ^* include a cyclopentadienyl ring, a condensed ring containing cyclopentadienyl (including but not limited to an indenyl ring and a fluorenyl ring), and the like. The most preferred cyclopentadienyl derivative is a cyclopentadienyl ring.

In the general formula (1), Q ¹ and Q ² are the same or different monoanionic ligands. Monoanionic ligands include 1) hydride, 2) halide, 3) substituted or unsubstituted hydrocarbyl group having 1 to 20 carbon atoms, 4) alkoxy group or aryloxy group, 5) amide group, and 6) Examples include, but are not limited to, phosphino groups.
Q ¹ and Q ² may be bonded to each other or together to form a so-called dianionic ligand. Examples of dianionic ligands include alkylidene, dienes, cyclometallated hydrocarbyl groups, and bidentate chelate ligands.

In the general formula (1), L is a neutral Lewis base. Neutral Lewis bases include tetrahydrofuran, diethyl ether, dimethylaniline, trimethylphosphine, lithium chloride and the like. L may be bonded to Q ¹ and / or Q ² to form a so-called multidentate ligand. In the general formula (1), w represents the number of neutral Lewis bases L. w is an integer of 0 to 3, preferably 0 to 1.

  As described above, the catalyst composition used in the present invention contains an ionic compound. Here, the ionic compound includes an ionic compound composed of a non-coordinating anion and a cation. The ionic compound is combined with the metallocene complex described above to cause the metallocene complex to exhibit activity as a polymerization catalyst. As the mechanism, it can be considered that the ionic compound reacts with the metallocene complex to generate a cationic complex (active species).

As the non-coordinating anion which is a constituent component of the ionic compound, for example, a tetravalent boron anion is preferable, and tetra (phenyl) borate, tetrakis (monofluorophenyl) borate, tetrakis (difluorophenyl) borate, tetrakis (tri Fluorophenyl) borate, tetrakis (trifluorophenyl) borate, tetrakis (pentafluorophenyl) borate, tetrakis (tetrafluoromethylphenyl) borate, tetra (tolyl) borate, tetra (xylyl) borate, (triphenyl, pentafluorophenyl) Examples thereof include borate, [tris (pentafluorophenyl), phenyl] borate, and tridecahydride 7,8-dicarbaundecaborate.
Of these non-coordinating anions, tetrakis (pentafluorophenyl) borate is preferred.

The cation that is a constituent component of the ionic compound includes a carbonium cation, an oxonium cation, an ammonium cation, a phosphonium cation, a cycloheptatrienyl cation, a ferrocenium cation having a transition metal, and the like.
Specific examples of the carbonium cation include tri-substituted carbonium cations such as a triphenyl carbonium cation and a tri-substituted phenyl carbonium cation. Examples of the tri-substituted phenyl carbonium cation include a tri (methylphenyl) carbonium cation and a tri (dimethylphenyl) carbonium cation.
Specific examples of ammonium cations include trialkylammonium cations, triethylammonium cations, tripropylammonium cations, tributylammonium cations, tri (n-butyl) ammonium cations and other trialkylammonium cations, N, N-dimethylanilinium cations, N N, N-diethylanilinium cation, N, N-2,4,6-pentamethylanilinium cation, etc., N, N-dialkylanilinium cation, di (isopropyl) ammonium cation, dicyclohexylammonium cation, etc. Can be mentioned.
Specific examples of the phosphonium cation include triarylphosphonium cations such as triphenylphosphonium cation, tri (methylphenyl) phosphonium cation, and tri (dimethylphenyl) phosphonium cation.

Among these cations, an anilinium cation or a carbonium cation is preferable, and a triphenylcarbonium cation is more preferable. That is, the ionic compound contained in the catalyst composition of the present invention may be a combination of those selected from the above-mentioned non-coordinating anions and cations.
Preferably, triphenylcarbonium tetrakis (pentafluorophenyl) borate, triphenylcarbonium tetrakis (tetrafluorophenyl) borate, N, N-dimethylanilinium tetrakis (pentafluorophenyl) borate, 1,1′-dimethyldimethylacetate Examples thereof include nium tetrakis (pentafluorophenyl) borate. These ionic compounds may be used individually by 1 type, and may be used in combination of 2 or more type.

Among these ionic compounds, triphenylcarbonium tetrakis (pentafluorophenyl) borate and the like are particularly preferable. In addition, Lewis acids that can react with transition metal compounds to form cationic transition metal compounds, such as B (C ₆ F ₅ ) ₃ and Al (C ₆ F ₅ ) _3, are used as ionic compounds. These may be used in combination with the above ionic compounds.
Furthermore, alkylaluminum compounds (aluminoxanes, preferably methylaluminoxane (MAO) or isobutyl modified methylaluminoxane (MMAO)), or combinations of alkylaluminum compounds and borate compounds can also be used as ionic compounds, and other ionic You may use it in combination with a compound. In particular, when the monoanionic ligand Q of the complex (general formula (1)) used in the present invention is other than alkyl or hydride (for example, when it is halogen), an alkylaluminum compound or an alkylaluminum compound It may be preferable to use a combination of borate compounds.

The catalyst composition used in the present invention can contain arbitrary components in addition to the metallocene complex and the ionic compound. Optional components include silane compounds and hydrogen. Examples of the silane compound include phenylsilane.
As the ionic compound in the catalyst composition, a compound composed of a tetravalent boron anion and a carbonium cation such as [Ph ₃ C] [B (C ₆ F ₅ ) ₄ ] is preferable. It is preferable that the complex and the ionic compound have a molar ratio of about 1: 1.

Hereinafter, the manufacturing method of the styrene-ethylene copolymer among the said styrene-type copolymers is demonstrated. As a specific procedure for producing a styrene-ethylene copolymer, for example, ethylene gas is continuously supplied into a solution containing styrene (preferably a toluene solution). To this is added the catalyst composition. The reaction temperature is preferably adjusted to about 25 to 35 ° C.
The amount of styrene used may be about 1,000 to 70,000 times in molar ratio to the complex (or ionic compound). If the amount of styrene is increased, the molecular weight of the resulting copolymer can be increased, and the styrene unit content can be increased.
Although the pressure of the ethylene gas supplied can be adjusted arbitrarily, it is about 0.01-0.2 MPa normally. By adjusting this pressure, the molecular weight of the copolymer can be adjusted, or the ethylene unit content can be adjusted.
The catalyst composition is preferably added as a solution (preferably a solution containing active species) obtained by reacting a complex and an ionic compound in a solvent (preferably toluene) in advance. The reaction time is preferably about several seconds to about 1 hour, particularly about 1 to 20 minutes when an Sc complex is used.

  After completion of the reaction, the produced copolymer can be precipitated by introducing the reaction mixture into methanol or the like. A styrene-ethylene copolymer can be obtained by filtering the precipitated copolymer and drying it. The styrene-ethylene copolymer thus produced is a random copolymer and may have a high syndiotacticity. In preferred embodiments, it may have a sharp molecular weight distribution.

On the other hand, after adding and polymerizing the above catalyst composition in a solution containing styrene (preferably a toluene solution), styrene in the system disappears (can disappear in a few minutes), and then ethylene gas is supplied. Thus, a styrene-ethylene block copolymer is obtained. In addition, after polymerizing ethylene, styrene may be supplied and polymerized.
The styrene-ethylene copolymer thus obtained has a syndiotacticity with a high styrene block chain and may have a sharp molecular weight distribution.

The styrene copolymer stretch-molded product of the present invention is a molded product obtained by stretching the styrene copolymer.
In order to obtain the stretched molded article of the present invention, first, a molding material containing the styrene copolymer is prepared. In this molding material, various additive components such as antioxidants, ultraviolet absorbers, light stabilizers, compatibilizers, nucleating agents, lubricants, and inorganic fillers are added as desired without departing from the object of the present invention. An agent, a flame retardant, an antistatic agent, a plasticizer, a colorant, and the like can be appropriately contained.
There is no restriction | limiting in particular in the preparation method of the said characteristic form material, A conventionally well-known method can be used. For example, the above-mentioned styrene copolymer and various components used as desired are a ribbon blender, a Henschel mixer, a Banbury mixer, a drum tumbler, a single screw extruder, a twin screw extruder, a conida, a multi screw extruder, etc. The desired molding material can be obtained by melting and kneading at a temperature that is preferably equal to or higher than the melting point of the styrenic copolymer to be used and at which the resin component does not decompose.
Although there is no restriction | limiting in particular about the form of the styrene-type copolymer stretch-molded article of this invention, A sheet | seat or a film-like thing is preferable. In order to produce a stretched molded product on this sheet or film, the molding material obtained as described above is formed into a film, and a stretched raw fabric is first prepared. The film forming method is not particularly limited, and conventionally known methods such as a melt extrusion method (extrusion method), an inflation method, a calendar method, and a solution casting method (casting method) can be employed.

Next, the original fabric for stretching is subjected to uniaxial or biaxial stretching using a conventionally known stretching method. A wet stretching method or a dry stretching method can be employed as the uniaxial stretching method, and a tenter method or a tube method can be employed as the biaxial stretching method. This biaxial stretching method includes a sequential biaxial stretching method and a simultaneous biaxial stretching method. From the viewpoint of stretchability, the original fabric for stretching is preferably stretched by about 2 to 10 times at a temperature not lower than the glass transition temperature and not higher than “melting point−10 ° C.”, more preferably 3 to 8 times. .
The film thus stretched may be subjected to heat treatment as necessary in order to reduce the alignment unevenness. Heat treatment is held for about 0.5 to 120 seconds at a glass transition temperature or higher and a melting point or lower, preferably “melting point −100 ° C.” or higher and “melting point −5 ° C.” or lower in a tensioned state or a restricted shrinkage state. It is advantageous to do so.
As other stretching methods, melt stretching, wet stretching, gel stretching, and the like can be employed.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
Production Example 1 (Synthesis of catalyst)
_{(1) LiCH 2 C 6 H} 4 N (CH 3) 2 -o synthetic N, N-dimethyl -o- toluidine 18ml of (0.12 mmol) hexane (50 ml) - diethyl ether (16 ml) solution, n- 50 ml of BuLi 2.6 mol / L hexane solution was added dropwise over 25 minutes. After stirring for 45 hours, the precipitate was filtered off. The obtained solid was washed with 40 ml of hexane three times and then dried under reduced pressure to obtain 13 g of LiCH ₂ C ₆ H ₄ N (CH ₃ ) ₂ -o (yield 77%).
(2) Synthesis of Sc (CH ₂ C ₆ H ₄ N (CH ₃ ) ₂ -o) ₃ Anhydrous ScCl ₃ (1.0 g) 6.6 mmol in THF (tetrahydrofuran) suspension (10 ml) was added at room temperature for 1 hour. The mixture was stirred, and a solution of 2.8 g (20 mmol) of LiCH ₂ C ₆ H ₄ N (CH ₃ ) ₂ —o obtained in (1) above was added dropwise thereto and stirred for 12 hours. After the solvent was distilled off, the target product was extracted with toluene. This target product was purified by recrystallization to obtain pale yellow crystals. The yield was 45%.
_{(3) Cp'Sc (CH 2 C} 6 H 4 N (CH 3) 2 -o) Sc obtained in ₄ Synthesis of _{(2) (CH 2 C 6} H 4 N (CH 3) 2 -o) _{3 To} 2.0 g (4.5 mmol) of THF solution (10 ml), commercially available Cp′H = (C ₅ (CH ₃ ) ₄ H (Si (CH ₃ ) ₃ )) 1.1 g (5.4 mmol) of THF The solution was added. The mixture was stirred at 70 ° C. for 12 hours to be reacted. After completion of the reaction, the solvent was distilled off, and the target product [(1,2,3,4-tetramethyl-5-trimethylsilylcyclopentadienyl) bis (N, N-dimethylaminobenzyl) scandium] was extracted with toluene. . The target product was purified by recrystallization to obtain 1.7 g of pale yellow crystals. The yield was 67%.

Production Example 2 (Production of styrene-ethylene copolymer having a syndiotactic structure)
To a 1 L autoclave that had been dried by heating, 350 ml of dehydrated toluene and 47 ml of styrene were added at room temperature under a nitrogen atmosphere. After adjusting the temperature to 30 ° C. with stirring, (1,2,3,4-tetramethyl-5-trimethylsilylcyclopentadienyl) bis (N, N-dimethylaminobenzyl) obtained in Preparation Example 1 was obtained. 15 ml of a solution in which 0.021 mmol of scandium and 0.021 mmol of triphenylcarbenium tetrakispentafluorophenylborate were previously mixed was added. Subsequently, ethylene was introduced, and polymerization was carried out for 5 minutes while maintaining the pressure at 0.03 MPa (0.3 kg / cm ² ). After the completion of the polymerization reaction, the reaction product was put into a mixed solution of methanol and hydrochloric acid, sufficiently stirred, filtered, further washed thoroughly with methanol, dried, and 0 styrene-ethylene copolymer 35. 6 g was obtained. The obtained copolymer had an ethylene unit content of 9 mol% and a styrene unit content of 91 mol%, a melting point of 265 ° C., a weight average molecular weight (Mw) of 188,000, and a molecular weight distribution (Mw / Mn) of 1.3. The pentad racemic fraction [rrrr] exceeded 99.0%.

Example 1 [Production of stretch-molded article (biaxial stretching)]
The styrene-ethylene copolymer obtained in Production Example 2 was pelletized using a twin screw extruder (260 ° C. setting). From this pellet, an original fabric for drawing having a thickness of 250 μm was prepared using a 25Φ single-screw extruder (300 ° C. setting). As biaxial stretching, sequential biaxial stretching was performed using a table tenter. The draw ratio (MD × TD) was 3 × 3.4. Heat treatment was performed in a ventilated oven at 200 ° C. for 30 seconds to obtain a stretch-formed product. The physical properties of the obtained stretched molded product were evaluated by the following methods. The results are shown in Table 1.

(1) Tensile properties (tensile modulus, tensile yield strength, tensile breaking strength and tensile breaking elongation)
It measured based on JISK7113.
(2) Elmendorf Tear Strength Measured according to JIS K 7128-2.
(3) Film Impact The film impact was measured using a “film impact tester” manufactured by Toyo Seiki Seisakusho.
(4) Total haze, external haze, and internal haze Measured according to JIS K 7105.

Comparative Example 1
Using a syndiotactic polystyrene for stretched film (trade name: Zalec F2907, manufactured by Idemitsu Kosan Co., Ltd.), a stretch raw material was produced in the same manner as in Example 1, and then a biaxial stretching was performed to produce a stretch molded product. The physical properties were evaluated by the same method. The results are shown in Table 1.

  The styrene copolymer stretch-molded article of the present invention is suitable for applications that require heat resistance, toughness and transparency at the same time.

Claims (1)

  It has a syndiotactic structure consisting of 5 to 99 mol% of styrene derivative units and 95 to 1 mol% of olefin units, and the stereoregularity [rrrr] of the repeating unit chain composed of styrene derivatives is 80% or more. A styrene copolymer stretch molded article obtained by stretching a styrene copolymer having a molecular weight distribution of 1.3 or less.